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PipeStreaming with ObjectStreaming App. - Freezes

1 reply on 1 page. Most recent reply: May 12, 2003 2:41 AM by Adam Duffy

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Natalie

Posts: 2
Nickname: natalya
Registered: May, 2003

PipeStreaming with ObjectStreaming App. - Freezes Posted: May 5, 2003 12:05 PM
Reply to this message Reply
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Hi ?V Please help! I have a multi-threaded application that involves three threads: Filter, EventRecognizer, and Checker. Initially the application communicated successfully using PipeStreaming with DataStreaming. Now I want to communicate non-primitive objects, so I am changing the communication to be PipeStreaming with ObjectStreaming. Unfortunately the execution freezes somewhere between communication of Filter to EventRecognizer, I think?K ?? any ideas and/or suggestions? Why is this happening? How do I fix it?
I have attached some bits of the application code below. Any ideas/suggestions to get this working would be most appreciated.
Unfortunately, the code is quite detailed so I did my best to extract the causing parts. Feel free to contact me at natalieabowles@hotmail.com as well.
Thank you!

[b]public class[/b] MaCMain {

[b]public static void[/b] main(String args[]) {

[b]int[/b] currentArg = 0;

[b]try[/b] {

[i]/* Pipe */[/i]
PipedInputStream erChkInput =
mac.types.interfaceERChecker.Pipe.erChkInput;
PipedOutputStream erChkOutput =
mac.types.interfaceERChecker.Pipe.erChkOutput;
erChkInput.connect(erChkOutput);
PipedOutputStream chkSteerOutput = null;

[i]/* Target System */[/i]
Class targetSystem = Class.forName(args[currentArg++]);
Method mainMeth = targetSystem.getMethod("main",
new Class[] {Class.forName("[Ljava.lang.String;")});
[b]int[/b] systemArgsLength = 0;

[i]/* Event Recognizer part */[/i]
System.out.println(mac.Version.info(
"MaC Event Recognizer: Monitor of Instrumented\n" +
" Java Program"));

new EventRecognizerMain(erChkOutput,
args[currentArg++],
args[currentArg++]).run();

[/i]/* checker part */[/i]
System.out.println(mac.Version.info(
"MaC Runtime Checker: Checker of Monitored Behavior\n" +
" for Run-time Formal Analysis"));

if( currentArg+2 == args.length && args[currentArg+1].equals("-s"))
chkSteerOutput =
mac.types.steeringTypes.Pipe.chkSteerOutput;

if( currentArg+1 != args.length && currentArg+2 != args.length)
throw new Exception();

(new CheckerMain(0, null, 0, args[currentArg], null,
erChkInput, chkSteerOutput)).run();

[i]/* start target system */[/i]
(new TargetSystem(mainMeth, param)).start();
}
catch(Exception e) {
System.err.println("** Error: incorrect arguments ... ");
System.err.println("** Usage is ... ");
System.err.println(" java mac.MaCMain targetsystem_class"+
" targetsystem_arguments");
System.err.println(" pedl.out instrumentation.out"+
" medl.out [-s]");
System.exit(1);
}
}
}
[b]public final class [/b]Filter
{
??[b]??static boolean[/b] initDone = false;
[i]/** A list of monitored objects, methods and fields */

/** Network-related variables */[/i]
[b]static[/b] Socket s = null;
[b]static[/b] OutputStream sout=null;
[b]////public static DataOutputStream oStream;
public static ObjectOutputStream oStream;[/b]

[b]public final static Object[/b] lock = new Object();

[i]/* For monitoring object */[/i]
[b]public static[/b] PedlInstrObject instrumentationOut = null;

[i] /** This method performs 3 jobs
* 1. It initialize communication channel to an event recognizer.
* 2. It sets the size of buffers and other configurations based on
* run-time parameters
* 3. It generates a filter thread. A filter thread performs book-keeping of
* address/name table and actuall communication for making low overhead
* to original program
*/[/i]
[b]static public void ??[/b]??init(String host, int port, int period, boolean deltaValue){ [i]// Communication channel
// If initialization is already performed, do not do it again[/i]
??[b]??if??[/b]??( initDone ) { return;}

initDone = true;

[b]try {
if [/b](port == 0 && host == null)
sout = Pipe.filterEROutput;
[b] else {[/b]
s = new Socket(host,port);
sout = s.getOutputStream();
}

[i]// For efficiency, use BufferedOutput[/i]
[b]////oStream = new DataOutputStream(sout);
oStream = new ObjectOutputStream(sout);[/b]


}

[b]public static void[/b]init(String filename, int period, boolean deltaValue) {
[b]if[/b]( initDone ) { return;}
initDone = true;


/* Usa: Check for timestamps */
System.out.println("Filter:period -> "+period);
??[b]??try{[/b]
////oStream = new DataOutputStream(
oStream = new ObjectOutputStream(
new FileOutputStream(filename,false));
??[b]??if[/b](period != 0 ) new TimeStamp(period);
SendMethods.delta = deltaValue;
}catch(IOException e) {
System.out.println("I Caught this IOException in Filter.java: " + e);
System.err.println("In init(String), " + e);
}
}
public static void init(int period, boolean deltaValue) { // general output stream
if( initDone ) { return;}
initDone = true;

/* Usa: Check for timestamps */
System.out.println("Filter:period -> "+period);

if( period != 0 ) new TimeStamp(period);
SendMethods.delta = deltaValue;
}

[i]/** This method is used for giving inputstream and output stream to the
* target application. targetClass should be fully qualified class name. parameter is is ignored */[/i]
??[b]??public static void[/b] hook(String targetClass, String[] args,
InputStream is, OutputStream os) {
??[b]??try{
////oStream = new DataOutputStream(os);
oStream = new ObjectOutputStream(os);[/b]
Class targetApp = Class.forName(targetClass);

Method main = targetApp.getMethod("main",
new Class[] {Class.forName("[Ljava.lang.String;")});
main.invoke(null, new Object[] { args});
oStream.close();
}catch (IOException ioe) {
System.out.println("I Caught this IOException in Filter.java: " + ioe);
} catch(Exception e) {System.err.println(e);System.exit(-1);
}


}
}
??[b]??public class[/b] EventRecognizer ??[b]??extends[/b] Thread {

??[b]??protected final int[/b] MAX_HEIGHT; // maximum height in tree
??[b]??public final static int[/b] startID = PedlInstrObject.startID;
OutputStream outStream;
InputStream inputStream;

??[b]??//protected DataInputStream primitiveIn;
protected ObjectInputStream primitiveIn;
////DataOutputStream events_conds_out;
protected ObjectOutputStream events_conds_out;[/b]

[i]// For reducing the run-time cost of creating an object of ErChkObject,
// I create the object once then change the contents of the
// object every time. [/i]
??[b]??protected[/b] ErChkObject obj ;
??[b]??protected[/b] InterfaceERChecker exportTBL;

??[b]??Vector[/b] monExecPoints;
??[b]??int[/b] numExecPoints;

??[b]??Vector[/b] monLocalVars;
??[b]??int[/b] numLocalVars;

??[b]??Vector[/b] monGlobalVars;
??[b]??int[/b] numGlobalVars;

??[b]??int[/b] num = 0; [i]// number of event received so far[/i]

??[b]??public[/b] EventRecognizer(InputStream inStream, OutputStream outStream,
ParserErObject pedl_out, PedlInstrObject objMonEntities){
this.parseTree = pedl_out.getParseTree();
this.symbolTbl = pedl_out.getSymbolTable();
this.exportEvents = pedl_out.getExportedEvents();
this.exportConditions = pedl_out.getExportedConditions();
this.conditions = pedl_out.getConditions();
this.events= pedl_out.getEvents();
this.lastOccurrenceTimes = new long[events.length];
period = objMonEntities.tickPeriod;
// Make varTypes : varId -> varType
varTypes = new int[objMonEntities.getNumMonEntities()
+startID];
varDeltaTypes = new int[objMonEntities.getNumMonEntities()
+startID];
}

monExecPoints = objMonEntities.getExecPoints();
numExecPoints = monExecPoints.size();

monLocalVars = objMonEntities.getLocalVars();
numLocalVars = monLocalVars.size();

monGlobalVars= objMonEntities.getGlobalVars();
numGlobalVars = monGlobalVars.size();

this.outStream = outStream;

[b]try {
////events_conds_out = new DataOutputStream(outStream);
events_conds_out = new ObjectOutputStream(outStream);

////primitiveIn = new DataInputStream(inStream);
primitiveIn = new ObjectInputStream(inStream);
} catch [/b](IOException ioe) {
System.out.println("I Caught this IOException in EventRecognizer.java: " + ioe);
}
hasTimeStamp = objMonEntities.isTimeStampRequired();
exportTBL = new InterfaceERChecker(
exportEvents,exportConditions,hasTimeStamp);

MAX_HEIGHT = parseTree.getHeight();
}

[b]public void[/b] run() {
[b]int dataType;
int varId=0;[/b]

[b]String[/b] type = null;
[b]byte[][/b] ba = new byte[200];
[b]Object[/b] value = null;

initializeSymbolTbl();

ObjectOutputStream oOut = new ObjectOutputStream(outStream);
oOut.writeObject(exportTBL);
oOut.flush();

[b]for(;;)[/b] {

[b]varId = primitiveIn.readByte();[/b]

// Special id sections such as time stamps
[b]switch[/b](varId ) {
case 0: System.err.println(
"Something wrong happens; ID 0 is received!");
break;
case 1: currentTargetTime += period; continue;
default:
}

resetSymbolTBL(); // reset updated flag.
[b]dataType = varId >= 0 ?
varTypes[varId] : varDeltaTypes[- varId ]; [/b]

[b]switch[/b](dataType) {
case DataTypes.SHORT:
value = getObjectValue(primitiveIn.readShort());
updateSymbolTBL(varId,value);
break;
case DataTypes.INT:
value = getObjectValue(primitiveIn.readInt());
updateSymbolTBL(varId,value);
break;
case DataTypes.LONG:
value = getObjectValue(primitiveIn.readLong());
updateSymbolTBL(varId,value);
break;
case DataTypes.FLOAT:
value = getObjectValue(primitiveIn.readFloat());
updateSymbolTBL(varId,value);
break;
case DataTypes.DOUBLE:
value = getObjectValue(primitiveIn.readDouble());
updateSymbolTBL(varId,value);
break;
case DataTypes.BYTE:
value = getObjectValue(primitiveIn.readByte());
updateSymbolTBL(varId,value);
break;
case DataTypes.CHAR:
value = getObjectValue(primitiveIn.readChar());
updateSymbolTBL(varId,value);
break;
case DataTypes.BOOLEAN:
// From Nov 27, method start/end is informed through
// boolean, not string
temp = primitiveIn.readBoolean();
[b]if[/b]( varId < // Execution point
numExecPoints+startID) {
value = temp ?
"end of " + monExecPoints.elementAt(
varId - startID) :
"start of "+monExecPoints.elementAt(varId - startID);
//System.out.println(varId+":"+value);
[b]} else[/b] value = getObjectValue(temp);

updateSymbolTBL(varId,value);
break;
case DataTypes.STRING: // Execution Point
value = primitiveIn.readUTF();
updateSymbolTBL(varId,value);
break;
default:
}

evaluateBackward(varId, value);

sendSignals();

}

}[b]
catch[/b](EOFException e){
System.out.println("ER: Trace is completely read.");
[b]try[/b]{outStream.flush();}
[b]catch[/b](IOException ioe) {System.err.println(ioe);}
System.exit(0);
} [b]catch[/b](IOException e){
if (e.getMessage().equals("Pipe broken") ||
e.getMessage().equals("Write end dead")) {
System.out.println("ER: Trace is completely read.");
[b]try{[/b]
outStream.flush();
}
[b]catch[/b](IOException ioe) {System.err.println(ioe);}
}
[b]else[/b]
e.printStackTrace();
}
}
[i]/**
* Given snapshot object from the filter, it checks what events
* happen or what conditions are satisfied. Then it sends detected
* events and conditions to the run-time checker[/i]
*/
[b]Object[/b] getObjectValue(short s) {
return (new Short(s));
}
[b]Object[/b] getObjectValue(int i) {
return (new Integer(i));
}
[b]Object[/b] getObjectValue(long l) {
return (new Long(l));
}
[b]Object[/b] getObjectValue(float f) {
return (new Float(f));
}
[b]Object[/b] getObjectValue(double d) {
return (new Double(d));
}
[b]Object[/b] getObjectValue(char c) {
return (new Character(c));
}
[b]Object[/b] getObjectValue(boolean b) {
return (new Boolean(b));
}
[b]Object[/b] getObjectValue(int varId, byte b) {
return (new Byte(b));
}
[b]Object[/b] getObjectValue(int varId, String s) {
return s;
}

[b]void[/b] updateSymbolTBL(int varId, Object value) {
if( - startID < varId && varId < startID ) {
System.err.println("varId:" + varId +
" must not be in the reserved index range "
+"(-"+startID+", "+startID+") at updateSymbolTBL()!");
}
String varName = null;
[b]int _varId = varId >= 0 ? varId - startID :
- varId - startID;[/b]



void sendSignals() {

[b]if[/b](hasTimeStamp) events_conds_out.writeLong(currentTargetTime);
events_conds_out.writeByte(numOccurredEvents);
events_conds_out.writeByte(numTrueConds);
events_conds_out.writeByte(numFalseConds);
events_conds_out.writeByte(numUndefConds);
} [b]catch[/b](IOException e3) { System.err.println(e3);}

for(int i=0; i < numOccurredEvents; i++) {
values = occurredEventValues[i];

// Currently, only update(x) contains a value vector which
// contains only 1 value. endM and startM should have a
// value vector, but not yet implemented
// Other types of events have null as a value vector
if( values.isEmpty() ) {
typeEventValue = DataTypes.NONE;
} else {
value = values.elementAt(0);

if( value instanceof Integer)
typeEventValue = DataTypes.INT;
else if( value instanceof Short)
typeEventValue = DataTypes.SHORT;
else if( value instanceof Long)
typeEventValue = DataTypes.LONG;
else if( value instanceof Float)
typeEventValue = DataTypes.FLOAT;
else if( value instanceof Double)
typeEventValue = DataTypes.DOUBLE;
else if( value instanceof Byte)
typeEventValue = DataTypes.BYTE;
else if( value instanceof Character)
typeEventValue = DataTypes.CHAR;
else if( value instanceof Boolean)
typeEventValue = DataTypes.BOOLEAN;
else if( value instanceof String)
typeEventValue = DataTypes.STRING;
else if( value instanceof ThreeValued)
typeEventValue = DataTypes.UNDEF;
else System.err.println(value +
" is not primitive numeric type nor String");
}
[b]try{[/b]

//events_conds_out.writeUTF(occurredEventNames[i]);
events_conds_out.writeByte(
exportTBL.getID(occurredEventNames[i]));
// System.out.println(exportTBL.getID(occurredEventNames[i]));

events_conds_out.writeByte(typeEventValue);
[b]switch[/b](typeEventValue) {
case DataTypes.NONE: // No value
break;
case DataTypes.SHORT:
events_conds_out.writeShort(((Short)value).shortValue());
break;
case DataTypes.INT:
events_conds_out.writeInt(((Integer)value).intValue());
break;
case DataTypes.LONG:
events_conds_out.writeLong(((Long)value).longValue());
break;
case DataTypes.FLOAT:
events_conds_out.writeFloat(((Float)value).floatValue());
break;
case DataTypes.DOUBLE:
events_conds_out.writeDouble(
((Double)value).doubleValue());
break;
case DataTypes.BYTE:
events_conds_out.writeByte(((Byte)value).byteValue());
break;
case DataTypes.CHAR:
events_conds_out.writeChar(
((Character)value).charValue());
break;
case DataTypes.BOOLEAN:
events_conds_out.writeBoolean(
((Boolean)value).booleanValue());
break;
case DataTypes.UNDEF: // false is dumb value
events_conds_out.writeBoolean(false);
break;
case DataTypes.STRING:
events_conds_out.writeObject((String)value);
break;
default: System.err.println(
"Incorrect type of value of event "
+ ev.getName() + " " + typeEventValue);
}
//System.err.println(occurredEventNames[i]+":"+values+"-"+num++ +"-:" + currentTargetTime);
// Deactivating events for next time instance
se = (SymtabEntry)symbolTbl.get( occurredEventNames[i]);
((SimpleNode)se.getValue()).setValue(new EventType(false));
} catch(IOException e1) { System.err.println(e1); }
}


}</code>


Adam Duffy

Posts: 168
Nickname: adamduffy
Registered: Feb, 2003

Re: PipeStreaming with ObjectStreaming App. - Freezes Posted: May 12, 2003 2:41 AM
Reply to this message Reply
Whenever I get code freezing somewhere I try and narrow down the exact line that it freezes at by using System.out.println statements.

Once I have that particular line (or small group of lines) then I put the following code around it

try
{
  // your code here
}
catch( Throwable t )
{
  t.printStackTrace();
  // or System.out.println( t ); if you prefer
}


It's typically something that has been closed and not been re-opened for some reason. If you have try statements in your code which contain variables referring to streams, then don't forget to use the finally statement.

For example,
OutputStream out = new FileOutputStream( "myfile.txt" );
try
{
   out.write( 234 );  // if this throws an exception
   out.close();       // the output stream will not be closed
}
catch( Exception e )
{
 
}


instead use the following

OutputStream out = new FileOutputStream( "myfile.txt" );
try
{
   out.write( 234 );  // if this throws an exception
}
catch( Exception e )
{
 
}
finally
{
  out.close();   // will always be closed even if exception is thrown
}


Hope this helps.

Adam

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